of berlin



UNITED STATES PATENT OFFICE.

CARL BASWITZ, OF'BERLIN, GERMANY.

METHOD OF REMOVING COPPER FROM TEXTILE PARCHMENTS.

SPECIFICATION forming part of Letters Patent No. 506,966, dated October17, 1893.

Application filed July 10, 1890. Serial No. 358.317. (No specimens.)

to this day been of slight value for finishing and dressing purposes asthe fabric, which has been treated with such oxid, shows no substantialchange in its original textile qualities after the evaporation of theammonia and the removal of the hydrate of copper oxid. But if vegetableparchment is dissolved in ammoniacal solution of copper and the textileimpregnated with the solution, as soon as the ammonia has evaporated,there remains thereon a layer, which is firmly connected with the fiberand the fabric possesses all the characteristic qualities of theparchment. The waste or refuse from parchment manufactories is suitablefor this purpose, t'. e., vegetable parchment produced by the reactionof sulphuric acid on paper.

To prepare the solution enough hydrate of copper is dissolved in ammoniaof the specific weight of 0.91 to give thirty grams of copper in eachliter of the solution, and then fifteen grams of vegetable parchmentmust be added. When the solution is applied to the fabrics, aprecipitate is formed by evaporating ammonia, which causes the fabric tobecome water proof. This precipitate is firmly connected with the fiberand contains a basic combination of copper, which is objectionable,since it makes the cloth heavy and stiff and involves a waste of copper.To remove this combination of copper on the fiber, the textile fabricsare treated with a ten per cent. solution of sulphate of ammonia inacetate of alumina, dissolved in water to a specific weight of 1.04. Bythis means a precipitate of basic sulphate of alumina isformed, whichenvelops in the fibers and makes the same uninflamrnable, and at thesame time recovers the copper for further use as a soluble acetate.

What I claim, and desire to secure by Letters Patent of the UnitedStates, is-

The process of treating textile fabrics, which consists in dipping themin a solution of vegetable parchment in ammoniacal oxid of copper, thenevaporatingthe ammonia, and finally treating them with a mixture ofsulphate of ammonia and acetate of alumina for the purpose of removingthe copper contained in the textile and at the same time making thefabric uninfiammable, substantially as described.

In witness whereof I have hereunto set my hand in presence of twowitnesses.

CARL BASWITZ.

